We present simultaneous dual-frequency VLBA 2 GHz and 8 GHz
observations of 133 of the 560 extragalactic sources for which
positions were reported by Johnston et al. (1995,AJ,110,880). These
observations represent the second in a series of observations intended
to image the entire set of sources presented by Johnston et al. and,
together with previously reported observations, bring the total number
of sources observed so far to 169. We use these data to quantify the
magnitude of the expected effect of intrinsic source structure on
astrometric bandwidth synthesis Very Long Baseline Interferometry
observations. We also calculate a source ``structure index'' which can
be used as an estimate of the astrometric quality of the sources.

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